The invention relates to an igniter unit for an inflator.
A typical igniter unit comprises a base in which electric contact pins are arranged, and a plug for plugging into the base to contact the contact pins, and serves to convert an electric pulse furnished via the contact pins in such a manner that a gas generant of the inflator is reliably ignited. The quantity of compressed gas then made available by the gas generant may be used, for example, to actuate a piston of a linear drive as employed, for example, for a belt tensioner or for deploying a gas bag of a gas bag restraint system.
One salient requirement on such an igniter unit is that reliable contacting of the contact pins must be assured. This requires, in particular, that the contact pins must not be damaged neither when plugging the plug into the base nor when the plug is plugged in the base.
This is achieved in an igniter unit which comprises a base in which electric contact pins are arranged and a plug for plugging into the base to contact the contact pins. The plug is provided with at least one key and the base is provided with at least one guide groove for the key. In this arrangement, the plug is prevented from twisting relative to the base and thus relative to the contact pins. Any torque acting between the plug and the base is directed by means of the guide groove and the key directly into the base so that there is no load on the contact pins. This assures that the contact pins cannot be sheared off, neither when plugging the plug into the base nor later when the plug is plugged in.
Preferably two keys and two guide grooves are provided arranged angularly spaced away from each other by an angle other than 180xc2x0 to thus achieve keying, i.e. ensuring that the plug can only be plugged into the base in its one and only correct orientation.
Preferably the base is provided with a collar adapted for engaging a boss on the plug. This collar may be flanged or crimped so that the plug, when plugged into the base, is non-releasably connected thereto.
According to a preferred embodiment of the invention it is provided for that a sealing ring is disposed between the base and the plug. This prevents the ingress of moisture and dirt into the interior of the igniter unit to thus ensure reliably contacting of the contact pins even over a long operating period.
Preferably arranged in the base is an igniter from which the electric contact pins protrude. The contact pins are thus designed as an integral component of the igniter, making simple assembly of the igniter unit possible. The base then merely serves as a link between the igniter provided with the contact pins and the plug plugged onto the contact pins.
Advantageous embodiments of the invention read from the sub-claims.